How to create Enumerable “get” property?

Yes, this is for homework… but I'm stuck on this topic. I can't seem to grasp how to write an Enumerable property. I need to pass an array to a constructor and then create two Enumerable properties. One property will distinguish the even numbers and the other property will distinguish the odd numbers.

Would anyone know of a good resource online to explain Enumerable properties? I can find stuff related to Enumerable, but having a tough time finding stuff about properties and Enumerables.